Various means for covering and uncovering trailers for trucks, and openings thereto, are known in the art. Several of such means utilize tarpaulins for covering and uncovering access points (which can vary in size from a few square feet to openings comprising the entire side of a trailer) by selectively rolling the tarpaulin up about a rod or spindle, to uncover the access point, or unrolling the tarpaulin from the rod or spindle, to cover the access point. Many of such tarpaulin systems require additional arms that slide, retract, telescope or elongate in order to create a controlled means for the tarp to roll or unroll either vertically or horizontally about the truck body.